The invention relates to a roping-down device including a swivelling reel which is disposed in a housing for winding up a hauling means, an anchoring device and a load suspension device which are attached at the free end of the hauling means and on the housing respectively, and a braking device with a brake rotor, which is connected for operation with the reel, and a brake stator which is mounted on the housing and receives the brake rotor, whereby the braking effect increases as the unwinding and, thus, the rotating rate of the brake rotors increases.
Such a roping-down device with the help of which people may escape from buildings on fire, which, however, may also be used for descending loads, is already known from DE-B 11 10 014. In this document the hauling means is formed by a rope which is wound up on the rope reel in several layers. The swivelling rope reel, which, upon roping down, is rotated by the suspended load, is connected with the shaft of the brake rotor via a chain drive, said brake rotor running separately on bearings and being laterally offset with axle distance from the rope reel in the housing. The brake rotor is provided with associated brake shoes which are guided by journals engaging in grooves and are disposed to be dislocated with respect to the brake rotor so that they are dislocated radially to outside under the influence of the centrifugal force when the brake rotor is rotating and thereby are pressed against the inner circumferential surface of a brake stator ring mounted on the housing which ring encloses the brake rotor only on its outer circumference.
In the case of this roping-down device the anchoring device is secured on the housing and the load suspension device, which has the form of a loop, is attached on the free end of the rope so that the roping-down device itself is not descended and the rope is rewound by means of a flat spiral spring, which is disposed in the device and extends upon roping-down, after the person which has been saved has been freed and/or the load has been taken off on the ground. However, it is also provided within the scope of the invention to exchange the anchoring device and the load suspension device so that the free end of the rope or hauling means is, for instance, anchored on a window cross or otherwise and the roping-down device slides to the ground together with the person and/or the load, as is also already known (DE-A-28 31 449).
The first-mentioned known roping-down device has the advantage that the rope is slowed down automatically and with a braking force which is proportional to the rate of roping down so that a maximum descending rate is achieved which corresponds to the suspended weight and which can be varied by adjusting the dimensions of the roping-down device and, adjusting the dimensions of the braking surfaces, such that there is no risk of incurring injuries even if a heavy person, weighing, for instance, 100 kp, descends. Consequently, a correspondingly softer hitting of the ground is in a desirable manner achieved in the case of the descent of lighter persons (women and children). In particular, it is not necessary that the person which is roped down operates itself the brake or regulates it in order to achieve an individual descending rate, as is the case with the second-mentioned, co-descending roping-down device, which is provided with a crank handle for regulating the effective braking force. We are afraid that in the case of an emergency, and/or in the particular situation in which a building is on fire, mistakes will be made in connection with the operation of the brake even if it is extremely simple to operate, which makes the success of the descent doubtful.
Despite the useful automatic braking effect and the adjustment of the descending rate connected therewith, the known roping-down device described at the beginning cannot fully meet the demands to be made. In particular, operating faults may in the individual case occur as a result of excessive frictional adhesion occurring at the guide journals of the centrifugal shoe brake and/or excessive losses of power in the chain drive between the rope reel and the brake rotor and/or too great adhesive power between adjacent windings of the coiled-up rope so that the rope reel does not start rotating despite the suspended load or the brake does not develop the expected full effect during roping down. Such catastrophic operational faults are favoured by the fact that the roping-down device is normally used only in rare emergencies and after it has been stored for years without its efficiency having been checked. It is obvious that the described danger of failure will be the greater the higher the number of possible sources of fault, which still add to the effect of each other. In this context it must further be pointed out that also excessive abrasion or damage of the brake linings may be the cause for an insufficient braking action and, thus, for a danger for the persons roped down. As far as this is concerned, multiple use of the roping-down device as well as the stress of the brake linings through the braking power which is transformed into heat, affect the functional efficiency. Finally, the known device for roping down includes a great number of component parts, is correspondingly heavy, and is constructed in a less compact way.
It is further known to take in and carry away the kinetic energy to be taken in before persons or loads which are roped down reach the ground (DE-A 48 670). There are provided comparatively large rectangular radial wings which are disposed on the outer side of a wall of a housing and, beside that, act upon the surrounding air without a housing. On the wing tips auxiliary wings which swing out under the influence of the centrifugal power rest on bearings and increase the effective wing surface beyond a predetermined rotating velocity. With the aid of such air wings, which operate substantially without pressure in the open air, only a comparatively weak braking effect can be achieved even if a correspondingly large wing surface is used. Correspondingly, they are used in a device with a rope sheave on which the rope is not wound up, but deflected between its ends which hand down to the ground. On the one end of the rope a cage is suspended, on the other end of the rope a counterweight which is heavier than the cage, so that the latter descends only upon corresponding loading. This means that the described device belongs to a different sort which is heavy and cumbersume and the rope sheave and air vane of which are in operating connection by means of a transmission with four sprockets, whereby a transmission of velocity to the wing shaft takes place in order that the air vanes are braked at all by the air.